The rainfall event that occurred in Western Australia on Thursday 9th and Friday 10th February 2017 is generally being referred to as a ‘1 in 50 year event’.
Significant flooding has been observed in river systems, as well as localised flooding within urban areas. However you may have been wondering why there was not more widespread flooding in urban areas – particularly since road pipe networks are typically only designed to carry smaller events (1 in 5 year ARI). The stormwater systems could have been conservatively designed, however the lack of flooding may also be due to these catchments not experiencing the type of storm that causes the most runoff.
Click this link to find out more:2017 Flood Information